Ask any dentist whether fluoridated water helps prevent tooth decay, and in all likelihood they will reply that the difference between those who drink it and those who don't is like night and day. Comparative studies have shown that, on average, the incidence of tooth decay among children in fluoridated communities is 15–50% less than it is in nonfluoridated communities. Yet after more than 60 years since the first intentional fluoridation of a public drinking water supply in Grand Rapids, Mich., the benefits and risks of fluoridation continue to be debated.

No other public health controversy has been so long-running and so divided, with each side refusing to listen to the other, R. Allan Freeze and Jay H. Lehr note in their book "The Fluoride Wars: How a Modest Public Health Measure Became America's Longest-Running Political Melodrama." Advocates of fluoridation say it prevents dental cavities with no health risks. Those opposed question the benefits of fluoridation and say it leads to dental fluorosis, a cosmetic condition in which teeth become mottled, as well as other health problems such as crippling skeletal fluorosis and even cancer.

The authors do an excellent job tracing the history of fluoridated drinking water, from the early 1900s when high levels of fluoride in water were first linked to brown stained teeth to the first intentional fluoridation of a public water supply in 1945. The book then follows the path of fluoridation in the U.S. until 2000, using various cities as case studies.

What started out in Grand Rapids with little opposition soon turned into the "longest running circus in town," the authors write. Fluoridation referenda popped up in cities across the U.S., and pro- and antifluoridation forces battled at town hall meetings. In most cases, "votes ended up within a point or two of 50:50."

The book is entertaining and easy to read, chock-full of interesting people and stories, beginning with the mystery of brown stained teeth in Naples, Italy, and Colorado Springs, Colo., at the dawn of the 20th century.

ON A MISSION

H. Trendley Dean set a threshold limit for fluoride in drinking water.

Credit: CDC

ON A MISSION

H. Trendley Dean set a threshold limit for fluoride in drinking water.

Credit: CDC

Fast forward 30 years to the company-owned town of Bauxite, Ark., home to a mining subsidiary of the Aluminum Co. of America (Alcoa). Children who drank water from the town's two wells also developed the mysterious mottled teeth. The book describes how Alcoa's chief chemist, H. V. Churchill, solved the mystery in 1931 when he detected high levels of fluoride in the town's water.

Churchill, however, was careful not to make a correlation between fluoride and mottled teeth, presumably to absolve Alcoa from blame, the authors note. Instead, Churchill wrote that no correlation could be made because detecting fluoride in water is "fraught with difficulty."

The book then turns to the National Institutes of Health, which was celebrating its first anniversary in 1931. The chief scientist of its Dental Research Section, H. Trendley Dean, was on a mission to find out whether fluoride was the sole cause of mottled teeth. He was also assigned to determine whether there was a threshold below which mottling does not occur and, ironically, to examine the costs of removing fluoride from water.

By the mid-1930s, Dean had determined that there was a clear relationship between mottled teeth and fluoride in drinking water. He also concluded that fluoride begins to blemish teeth at levels above 1 ppm.

It became increasingly clear that patients afflicted with mottled teeth suffered tooth decay less frequently than those without the condition. The authors describe how Dean became obsessed with this observation and by 1937 had shifted his work "from the role of fluoride in mottling to the role of fluoride in caries protection." It wouldn't be long before the idea of adding fluoride to water supplies that do not have enough was born.

Grand Rapids was chosen to be the first city to have its water fluoridated, in a trial carried out by the Public Health Service in 1945. After much consideration, the level of fluoride was set at 1 ppm, the value still used today by roughly two-thirds of all municipal water works in the U.S. The remaining one-third do not add fluoride.

Concerns over fluoridation are still voiced loudly today. Although some of them are far-fetched, others do have merit, the authors acknowledge. For example, antifluoridationists often point to the fact that dental cavities have decreased in both fluoridated and nonfluoridated communities in recent years. In earlier years, "on average, children in fluoridated communities experienced 50% less tooth decay than their cousins in nonfluoridated communities," Freeze and Lehr note. Today, some studies suggest that the difference could be as low as 15%.

The authors and many profluoridationists attribute the decline in tooth decay in nonfluoridated communities to the increase in fluoride exposure from sources other than drinking water, such as fluoridated toothpastes, processed foods and beverages, and air.

Evidence of such exposure brings the reader to an important question: Is the current fluoride dose of 1 ppm in public drinking water too high? Freeze and Lehr note that in 1986 the Environmental Protection Agency set the maximum safe dose of fluoride at 4 ppm, on the basis that cosmetic problems are not adverse health effects. The agency also set a secondary "nonenforceable standard established for aesthetic reasons" of 2 ppm. Many antifluoridationists argue that the combined exposure to fluoride from all sources brings current exposure levels dangerously close to the 4-ppm level.

A documented rise in dental fluorosis in children from fluoridated communities supports that contention. Freeze and Lehr point out that in a study Dean conducted in 1940, the prevalence of the condition was 13.6%. In contrast, a study conducted by the Ontario Ministry of Health in the late 1990s, reported a 51.3% prevalence. Most of those cases are in the very mild to mild categories, although the prevalence of moderate to severe cases is not insignificant, they add.

Crippling skeletal fluorosis, on the other hand, is extremely rare in the U.S. According to the book, only five cases have been documented in the U.S. in the past 35 years. Nonetheless, the World Health Organization estimates that more than 1 million people in India and China, where drinking water naturally contains 20 to 30 ppm fluoride, suffer from the disease.

Antifluoridationists continue to claim a link between fluoride and cancer. They point to studies dating back as far as 1950 that showed an increased rate of tumor growth in mice exposed to fluoride, even though those studies have been refuted by the scientific and medical communities.

The book gives pretty convincing evidence that fluoride is responsible for the near eradication of dental cavities and that it doesn't cause cancer at current exposure levels. But it probably contains too much detail for most readers about the makeup of teeth and how fluoride protects them.

Numerous reviews of water fluoridation have been published over the years, but most of them have failed to give equal treatment to both sides of the argument. "The Fluoride Wars" is one of the few that provides both sides of the controversy; however, most readers will find the book biased in favor of fluoridation.

If balance is truly what the authors aimed to achieve with this book, they should have avoided statements like, "Overall, the pro-fluoridation movement is the clear winner on the credibility front," or "there seems little doubt, based on current scientific and medical understanding, that fluoridation does more good than harm." They should have let the readers decide for themselves.

Throughout the book, profluoridationists come across as traditional, mainstream scientists who tried to keep the controversy on rational ground and whose views are endorsed by the medical and dental establishments. Antifluoridationists, on the other hand, are portrayed as conspiracy theorists, alarmists, fringe scientists, crackpots, or coming from grassroots organizations that view the medical establishment with disdain.

Although Freeze and Lehr acknowledge that a few respected scientists have adopted antifluoride views, they maintain that those scientists are in the minority. They describe opposition as living in a "strange but alluring world of fluoridation conspiracy theory." An entire chapter is devoted to fluorophobia and those conspiracy theories.

One leading conspiracy theory is that the aluminum industry lobbied hard for fluoridation so that it would create a market for the significant amount of fluoride waste it produces during the electrolytic process to make aluminum. Indeed, as the authors point out, "there was a period between 1957 and 1968 when Alcoa sold sodium fluoride to cities for the fluoridation of their water supplies."

Readers learn next that the phosphate fertilizer industry also generates large amounts of fluoride waste and actually priced Alcoa out of the fluoride market in the late 1960s. Since then, most of the fluoride added to water has come from the fertilizer industry.

Another conspiracy theory antifluoridationists often cite is that fluoridation of drinking water was used to cover up the hazards of toxic hydrogen fluoride gas emitted from industrial sources like aluminum smelters. According to the argument, if people are convinced that fluoride in drinking water is safe, it won't be hard to convince them that it is also safe to breathe the chemical in the air, thus giving industry the green light to emit higher amounts of the gas. Today, hydrogen fluoride emissions are well regulated.

The authors save the most bizarre theory for last—that the government is using fluoride in drinking water to control the minds of the population. "Let's face it. If you believe the mind-control arguments, you qualify as a true-blue, bona fide conspiracy lover," they write.

Although "The Fluoride Wars" is biased toward profluoridation, the authors should be commended for providing all of the facts of the controversy in one place. Their call for both sides to get together to study the health issues with reason and respect is also a worthwhile goal because, as they point out, perhaps then "this long-standing and somewhat silly dispute could finally be laid to rest."